U.S. Pat. No. 4,062,385, issued Dec. 13, 1977 to Katusha et al, shows a toner container having a containing portion with an opening on the bottom and a flange extending outward from the opening. A cover is slidably secured to the flange. A receiving apparatus for the container includes a sump cavity for receiving toner through the bottom of the container when the opening of the container is positioned directly above it. The container with the cover are positioned beside the cavity and the container portion is slid off the cover and over the cavity with the container portion flange sliding on a receiving surface that surrounds the cavity.
U.S. patent application Ser. No. 07/360,811, filed June 2, 1989, Hacknauer et al, discloses various improvements to the basic structure shown in the Katusha patent.
In the commercial embodiments of all of the above toner containers a paper cloth seal is adhesively affixed to the bottom of the flange surrounding the opening of the container to make sure that no toner escapes prior to the container being in its position over the sump. The seal itself is excellent for preventing the escape of toner as long as it maintains its integrity. However, it is important that the cover which is generally a stiff, planar sheet of plastic also cover the opening to protect the seal from being pierced by fingers or other objects. After use, the containing portion is slid back on the cover which prevents residual toner from escaping until it can be cleaned in recycling.
In the Hacknauer et al application, the cover includes protrusions from its top surface which act as a stop preventing separation of the cover and container portion by movement in a direction opposite to that movement which would take the containing portion over the sump. This stop prevents an attempt to insert the container incorrectly and also overshooting when the containing portion is moved back away from the sump onto the cover when empty.